Energy absorbing table for vehicles

ABSTRACT

An energy absorbing table includes a support assembly and a table assembly. The support assembly includes a sidewall support that mounts to a sidewall, a support post that attaches to a floor, and a table support assembly coupled to the sidewall support and the support post. The table assembly includes a tabletop, at least one energy absorbing assembly, and at least one linear guide assembly. The at least one energy absorbing assembly includes a pair of plunger assemblies secured to the tabletop, and a crush chamber assembly secured to the table support assembly. The crush chamber assembly is configured to slidably receive an end portion of each of the pair of plunger assemblies and includes a pair of energy absorption cores. The at least one linear guide assembly includes a linear guide secured to the tabletop, and a pair of mounts secured to the table support assembly.

TECHNICAL FIELD

The present disclosure relates generally to tables for vehicles, andmore particularly, to an energy absorbing table having a tabletop thattranslates upon impact of a threshold energy level while absorbing athreshold amount of the impact energy.

BACKGROUND

Large transportation vehicles such as trains, buses, boats, may havetables for use for work and entertainment during travel. Generally, suchvehicles do not include seatbelts. Because safety restraints are notcommon and are largely undesirable due to the various advantages oftravelling in large vehicles, when one of these vehicles is involved inan accident, passengers may be thrown around the interior of the vehicleand injured by fixtures in the interior of the vehicle.

Tables in large transportation vehicles are generally solidly built toprovide a stable work surface and to provide damage resistance due tojolts and vibrations common in vehicles. Because of the solid nature ofthe tables and the usefulness and proximity of the tables to seating,tables can present a danger to passengers in the case of an accident oremergency stop. In mass transportation vehicles such as trains thatcommonly have tables, during an accident or sudden stop a passengerseated at a table is likely to be thrown against the edge of a table.The impact of the passenger against the table can result in seriousinjury to the passenger by the table.

It is desirable to provide a table that reduces the level of impact withpassengers that results from sudden movement by the passenger. Theconcepts disclosed below address these needs and others.

SUMMARY

In one aspect of the disclosure, an energy absorbing table for a vehicleincludes a support assembly and a table assembly that is supported bythe support assembly. The support assembly includes a sidewall supportconfigured to mount to a sidewall of the vehicle, a support postconfigured to attach to a floor of the vehicle, and a table supportassembly having a first end coupled to the sidewall support and a secondend coupled to the support post. The table assembly includes a tabletop,at least one energy absorbing assembly, and at least one linear guideassembly. The energy absorbing assembly includes a pair of plungerassemblies secured to the tabletop, and a crush chamber assembly securedto the table support assembly. The crush chamber assembly is configuredto slidably receive an end portion of each of the pair of plungerassemblies and includes a pair of energy absorption cores. Each energyabsorption core is aligned with a respective one of the end portions.The linear guide assembly includes a linear guide secured to thetabletop, and a pair of mounts secured to the table support assembly.The pair of mounts are aligned and configured to slidably receive thelinear guide.

In another aspect of the disclosure, a table assembly for mounting to atable support assembly includes a tabletop, at least one energyabsorbing assembly, and at least one linear guide assembly. The energyabsorbing assembly includes a pair of plunger assemblies secured to thetabletop and a crush chamber assembly configured to be secured to thetable support assembly. The crush chamber assembly is further configuredto slidably receive an end portion of each of the pair of plungerassemblies, and includes a pair of energy absorption cores. Each energyabsorption core is aligned with a respective one of the end portions ofa plunger assembly. The linear guide assembly has a linear guide securedto the tabletop, and a pair of mounts configured to be secured to thetable support assembly. The pair of mounts are aligned and configured toslidably receive the linear guide.

It is understood that other aspects of table assemblies will becomereadily apparent to those skilled in the art from the following detaileddescription, wherein various aspects of assemblies are shown anddescribed by way of illustration. As will be realized, these aspects maybe implemented in other and different forms and its several details arecapable of modification in various other respects. Accordingly, thedrawings and detailed description are to be regarded as illustrative innature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of table assemblies will now be presented in thedetailed description by way of example, and not by way of limitation,with reference to the accompanying drawings, wherein:

FIG. 1 is a top perspective illustration of an interior of a passengervehicle, e.g., a railcar, including an energy absorbing table.

FIG. 2 is a side perspective illustration of an embodiment of the energyabsorbing table of FIG. 1 mounted to a sidewall and floor of a passengervehicle, and with passengers seated at the table.

FIG. 3 is a top perspective illustration of the energy absorbing tableof FIG. 2 mounted to a sidewall and floor of a passenger vehicle andadjacent two passenger seats, and including a table assembly and asupport assembly.

FIG. 4 is a bottom perspective illustration of the energy absorbingtable of FIG. 3 .

FIG. 5 is a bottom perspective illustration of a portion of the energyabsorbing table of FIG. 4 showing energy absorbing components of thetable assembly.

FIG. 6A is a cross-section perspective illustration through a portion ofthe energy absorbing components of the table assembly.

FIG. 6B is a cross-section perspective illustration through a portion ofthe tabletop of the table assembly.

FIG. 7 is a side perspective illustration of a passenger of FIG. 2 afterimpacting the edge of the energy absorbing table showing forwardtranslation of the tabletop of the table assembly.

FIG. 8 is a bottom perspective illustration of a portion of the energyabsorbing table showing energy absorbing components of the tableassembly after passenger impact of FIG. 7 .

FIG. 9 is a cross-section perspective illustration through a portion ofthe energy absorbing components of the table assembly after passengerimpact of FIG. 7 .

DETAILED DESCRIPTION

With reference to FIG. 1 , a passenger vehicle 100 in the form of arailcar includes an energy absorbing table 102 located between opposedpairs of passenger seats 104. The energy absorbing table 102 isconfigured to displace horizontally, in the direction of the seatbacks106, upon impact of sufficient force to an edge of the tabletop of theenergy absorbing table.

With reference to FIGS. 2 and 3 , the energy absorbing table 102includes a table assembly 202 and a support assembly 204. The supportassembly 204 is configured to be mounted to a sidewall 206 and a floor208 of a passenger vehicle. The table assembly 202 is configured to besecured to the support assembly 204.

With reference to FIGS. 3, 4, and 5 , the table assembly 202 includes atabletop 302 having a top surface 304 and an underneath surface 402. Apair of energy absorbing assemblies 404 a, 404 b are secured in part tothe underneath surface 402, and in part to the support assembly 204. Apair of linear guide assemblies 422 a, 422 b are also secured in part tothe underneath surface 402, and in part to the support assembly 204.With reference to FIG. 6B, in one configuration the tabletop 302comprises an aluminum skinned composite panel with a bonded edge thatextends around three sides of the tabletop to define opposed lengthedges 602, 604 and a width edge 606.

Note that in FIGS. 4 and 5 (and later in FIG. 8 ) the part, i.e., thetable support assembly 430, of the support assembly 204 to which theenergy absorbing assemblies 404 a, 404 b and linear guide assemblies 422a, 422 b are secured in part is shown transparent. This is done in orderto show components of the energy absorbing table 102 that are locatedbetween the underneath surface 402 of the tabletop 302 and the tablesupport assembly 430.

With reference to FIGS. 5 and 6A, each energy absorbing assembly 404 a,404 b includes a pair of plunger assemblies 406 a, 406 b and a crushchamber assembly 408 with an energy absorption core 420. The pair ofplunger assemblies 406 a, 406 b and crush chamber assembly 408 areformed of a rigid metal material, while the energy absorption core 420is formed of a flexible, crushable material. Each plunger assembly 406a, 406 b includes a bracket 407 and an extension member 409 that extendsfrom the bracket. The crush chamber assembly 408 includes a pair ofreceptacles 410 a, 410 b mounted to a base plate 424.

As previously mentioned, the energy absorbing assemblies 404 a, 404 bare secured in part to the underneath surface 402, and in part to thesupport assembly 204. To this end, the bracket 407 of each plungerassembly 406 a, 406 b of each energy absorbing assembly 404 a, 404 b issecured to the underneath surface 402 of the tabletop 302, while thebase plate 424 of each crush chamber assembly 408 of each energyabsorbing assembly 404 a, 404 b is secured to a table support assembly430 of the support assembly 204. The brackets 407 and base plates 424may be secured using mounting hardware (not shown).

Continuing with reference to FIGS. 5 and 6A, each receptacle 410 a, 410b of the crush chamber assembly 408 has a closed end 412 and an openedend 414. The pair of receptacle 410 a, 410 b are arranged side-by-sidesuch that the closed end 412 of one is adjacent the opened end 414 ofthe other. The opened end 414 of each receptacles 410 a, 410 b is alignwith and is sized to receive an end portion 416 of a respective one ofthe plurality of plunger assemblies 406 a, 406 b. The end portion 416 ofthe plunger assemblies 406 a, 406 b comprises a closed end surface 415that presents a solid surface for abutting contact with an end surface417 of the energy absorption core 420.

With reference to FIG. 6A, an energy absorption core 420 is inserted inthe interior space between the closed end 412 of the receptacle 410 a,410 b and the end portion 416 of the plunger assembly 406 a, 406 b. Insome embodiments, the energy absorption core 420 is sized to tightly fitwithin the interior of the receptacle 410 a, 410 b. To this end theenergy absorption core 420 has cross-section dimensions, e.g., heightand width, that are slightly less than the cross-section dimensions ofthe opened end 414 of the receptacle 410 a, 410 b into which it isinserted. In one configuration, the cross-section dimensions of theenergy absorption core 420 is on the order of 1 millimeter less than thecross-section dimensions of the opened end 414 of the receptacle 410 a,410 b. The length of the energy absorption core 420 may be less than,equal to, or slightly greater than the length of the interior length ofthe receptacle 410 a, 410 b into which it is inserted.

In cases where the length of the energy absorption core 420 is equal toor slightly greater than the length of the interior of the receptacle410 a, 410 b, the energy absorption core may be slightly crushed by theend portion 416 of the plunger assembly 406 a, 406 b during assembly ofthe table assembly 202, as the end portion is placed through the openedend 414 of the receptacle. The result of this assembly is the stateshown in FIG. 6A. In cases where the length of the energy absorptioncore 420 is less than the length of the interior of the receptacle 410a, 410 b, the length is such that during assembly of the table assembly202, the end portion 416 of the plunger assembly 406 a, 406 b is placedimmediately adjacent to or in abutting contact with the end of theenergy absorption core 420. In one configuration, the energy absorptioncore 420 comprises an aluminum honeycomb structure, such as 22 PCFTRUSSGRID™, manufactured by Gill Corp.

With reference to FIGS. 4 and 5 , each linear guide assembly 422 a, 422b includes a linear guide 502 slidably received by or engaged with apair of mounts 504 a, 504 b. Slidably engaged with or received by meansthat the linear guide 502 moves relative to the pair of mounts 504 a,504 b. More specifically, the pair of mounts 504 a, 504 b are fixed inplace and the linear guide 502 is configured to slide back and forthalong a guiding structure of the mounts 504 a, 504 b. The linear guide502 and mounts 504 a, 504 b are formed of a metal material. Aspreviously mentioned, the linear guide assemblies 422 a, 422 b are alsosecured in part to the underneath surface 402 of the tabletop 302, andin part to the support assembly 204. To this end, each the linear guide502 of a linear guide assembly 422 a, 422 b is secured to the underneath402 of the tabletop 302 with mounting hardware 506, while the mounts 504a, 504 b of each linear guide assembly 422 a, 422 b are secured to thetable support assembly 430 of the support assembly 204 with mountinghardware 508. The linear guide assemblies 422 a, 422 b provide stabilityto the tabletop 302 relative to the table support assembly 430,particularly during translation of the tabletop that may result fromimpact to the edge 602 of the tabletop.

With reference to FIGS. 3, 4 and 5 , the support assembly 204 includes asidewall support 426, a support post 428, and a table support assembly430. The sidewall support 426 includes an upper portion 432 and a lowerportion 434, each configured to be attached to a sidewall 206 withmounting hardware 436. The support post 428 includes a vertical post 438and base 440. The base 440 is configured to be attached to a floor 208.The table support assembly 430 is secured to the upper portion 432 ofthe sidewall support 426 and the upper end 442 of the vertical post 438and provides a horizontal structure upon which to secure the tableassembly 202.

With reference to FIGS. 7 and 8 , the energy absorbing table of FIGS. 1through 6B is configured such that upon application of a load ofsufficient impact force F to a length edge 602 of the tabletop 302, thetabletop (together with the linear guides 502 and relevant plungerassembly 406 a, 406 b) translates or moves in the direction of theforce. A load of sufficient impact force F may result, for example, froma crash that causes a passenger to impact the length edge 602 of thetabletop 302. As shown in FIG. 8 , guided, linear translation of thetabletop 302 in the direction of impact is provided by the slidableengagement between the linear guides 502 secured to the tabletop 302 andthe mounts 504 a, 504 b secured to the table support assembly 430.

With additional reference to FIGS. 8 and 9 , guided, linear translationof the tabletop 302 in the above described manner is accompanied by acorresponding translation of the plunger assemblies 406 a, 406 b securedto the tabletop 302 relative to the receptacle 410 a, 410 b of crushchamber assembly 408 secured to the table support assembly 430. Morespecifically, the plunger assembly 406 a adjacent the length edge 602upon which the force F is applied moves further in its associatedreceptacle 410 a, while the plunger assembly 406 b adjacent the oppositelength edge 604 moves out of its associated receptacle 410 b. As shownin FIG. 9 , the energy absorption core 420 within the receptacle 410 ais crushed by the plunger assembly 406 a and thereby absorbs the energyfrom the impact. The energy from the impact is absorbed and the mass isdecelerated within acceptable limits while maintainingcompartmentalization of the passengers. In one configuration, thetabletop moves or slides a distance no greater than approximately 6inches.

Thus, disclosed herein is an energy absorbing table 102 for a vehicle.The energy absorbing table 102 includes a support assembly 204 and atable assembly 202 that is supported by the support assembly. Thesupport assembly 204 includes a sidewall support 426 configured to mountto a sidewall 206 of the vehicle, and a support post 428 configured toattach to a floor 208 of the vehicle. The support assembly 204 alsoincludes a table support assembly 430 having a first end 431 a coupledto the sidewall support 426 and a second end 431 b coupled to thesupport post 428. The first end 431 a and the second end 431 b encompassrespective end regions of the table support assembly 430 that includemore than the respective edges of the table support assembly. The tablesupport assembly 430 may be mechanically coupled by securing hardware,e.g., bolts, fasteners, etc., to the sidewall support 426 and thesupport post 428 so as to present a substantially horizontal and levelsurface.

The table assembly 202 includes a tabletop 302, at least one energyabsorbing assembly 404 a, 404 b, and at least one linear guide assembly422 a, 422 b. In the embodiment shown in FIG. 4 , the table assembly 202includes a pair of energy absorbing assemblies 404 a, 404 b and a pairof linear guide assemblies 422 a, 422 b. A first energy absorbingassembly 404 a and a first linear guide assembly 422 a are located in aregion of the sidewall support 426, while a second energy absorbingassembly 404 b and a second linear guide assembly 422 b are located in aregion of the support post 428.

In other embodiments, the table assembly 202 may include a single energyabsorbing assembly and a single one linear guide assembly, each locatedtoward the center of the length of the tabletop 302. In otherembodiments, the table assembly 202 may include more than two energyabsorbing assemblies and more than two linear guide assemblies that maybe evenly distributed along the length of the tabletop 302.

Each of the one or more linear guide assemblies 422 a, 422 b includes alinear guide 502 that is secured to the tabletop 302, and a pair ofmounts 504 a, 504 b that are secured to the table support assembly 430.In one configuration, the tabletop 302 includes an underneath surface402 and the linear guide 502 is secured to the underneath surface, whilethe table support assembly 430 includes a top surface 608 and the pairof mounts 504 a, 504 b are secured to the top surface. The pair ofmounts 504 a, 504 b are aligned with and configured to slidably receivethe linear guide 502. Slidably received by means that the linear guide502 moves relative to the pair of mounts 504 a, 504 b. Morespecifically, the pair of mounts 504 a, 504 b are fixed in place and thelinear guide 502 is configured to slide back and forth along a guidingstructure of the mounts.

Each of the one or more energy absorbing assemblies 404 a, 404 bincludes a pair of plunger assemblies 406 a, 406 b that are secured tothe tabletop 302, and a crush chamber assembly 408 that is secured tothe table support assembly 430. In one configuration, the tabletop 302includes an underneath surface 402 and the pair of plunger assemblies406 a, 406 b are secured to the underneath surface, while the tablesupport assembly 430 includes a top surface 608 and the crush chamberassembly 408 is secured to the top surface. The crush chamber assembly408 is configured to slidably receive an end portion 416 of each of thepair of plunger assemblies 406 a, 406 b and includes a pair of energyabsorption cores 420. In other words, the end portion 416 of each of thepair of plunger assemblies 406 a, 406 b is slidably received by thecrush chamber assembly 408. Slidably received by means that the pair ofplunger assemblies 406 a, 406 b, including their respective end portion416, move relative to the crush chamber 408. More specifically, thecrush chamber 408 is fixed in place and the plunger assemblies 406 a,406 b, including their respective end portion 416, are configured andarranged relative to the crush chamber assembly to slide back and forthwithin structures of the crush chamber. With reference to FIG. 6A, eachof the energy absorption cores 420 is aligned with a respective endportion 416 of one of the plunger assemblies 406 a, 406 b. For example,the energy absorption core 420 may be axially aligned with a plungerassembly 406 a to place the end surface of the core in abutting contactwith an end surface of the plunger assembly.

In some embodiments, the crush chamber assembly 408 comprises a pair ofreceptacles 410 a, 410 b. Each receptacle 410 a, 410 b has a closed end412 and an opened end 414. The pair of receptacles 410 a, 410 b arearranged such that the closed end 412 of a first receptacle 410 a isadjacent the opened end 414 of a second receptacle 410 b, and the openedend 414 of each receptacle is aligned with and is sized to receive anend portion 416 of a respective one of the pair of plunger assemblies406 a, 406 b. In this embodiment, a first core of the pair of energyabsorption cores 420 is located in the first receptacle 410 a and asecond core of the pair of energy absorption cores is located in thesecond receptacle 410 b. The receptacles 410 a, 410 b have an interiorhaving a width substantially equal to the width of the energy absorptioncore, a height substantially equal to the height of the energyabsorption core, and a length greater than the length of the energyabsorption core.

In one configuration, each energy absorption core 420 is configured toabsorb at least 6250 in.-lbf of energy when a load applied in adirection of movement of the end portion of a plunger assembly reaches2250 lbf. Each energy absorption core 420 may comprise a metal materialhaving a honeycomb structure. In one embodiment, each energy absorptioncore 420 has a height in the range of 0.6 to 1.0 inches, a width in therange of 0.6 to 1.0 inches, and a length in the range of 5.0 to 7.0inches. Alternatively, the energy absorption cores may be described interms of its volume, e.g., length×width×height.

In other embodiments, the energy absorbing assemblies 404 a, 404 b maybe configured to absorb different energy levels. For example, energyabsorption may be increased by increasing the interior space of thereceptacles 410 a, 410 b and increasing the dimensions or volume of theenergy absorption cores 420. Furthermore, while the example embodimenttable assembly 202 disclosed is in relation to a table having a lengthof 44 inches and a width of 28 inches, table assemblies having tables ofdifferent sizes may be designed, wherein features of the energyabsorbing assemblies 404 a, 404 b, e.g., receptacle length,cross-section dimensions, etc. may be increased or decreased to absorbdifferent energy levels as may be required by industry standards.

The various aspects of this disclosure are provided to enable one ofordinary skill in the art to practice the present invention. Variousmodifications to exemplary embodiments presented throughout thisdisclosure will be readily apparent to those skilled in the art. Thus,the claims are not intended to be limited to the various aspects of thisdisclosure, but are to be accorded the full scope consistent with thelanguage of the claims. All structural and functional equivalents to thevarious components of the exemplary embodiments described throughoutthis disclosure that are known or later come to be known to those ofordinary skill in the art are expressly incorporated herein by referenceand are intended to be encompassed by the claims. No claim element is tobe construed under the provisions of 35 U.S.C. § 112, sixth paragraph,unless the element is expressly recited using the phrase “means for” or,in the case of a method claim, the element is recited using the phrase“step for.”

What is claimed is:
 1. An energy absorbing table for a vehicle, theenergy absorbing table comprising: a support assembly including: asidewall support configured to mount to a sidewall of the vehicle, asupport post configured to attach to a floor of the vehicle, and a tablesupport assembly having a first end coupled to the sidewall support anda second end coupled to the support post; and a table assemblyincluding: a tabletop, at least one energy absorbing assembly having: apair of plunger assemblies secured to the tabletop; and a crush chamberassembly secured to the table support assembly, the crush chamberassembly configured to receive an end portion of each of the pair ofplunger assemblies and including a pair of energy absorption cores, eachenergy absorption core aligned with a respective one of the endportions, and at least one linear guide assembly having: a linear guidesecured to the tabletop, and a pair of mounts secured to the tablesupport assembly, wherein the pair of mounts are aligned and configuredto receive the linear guide.
 2. The energy absorbing table of claim 1,wherein each energy absorption core is configured to absorb at least6250 in.-lbf of energy when a load applied in a direction of movement ofthe end portion of a plunger assembly reaches 2250 lbf.
 3. The energyabsorbing table of claim 2, wherein each energy absorption corecomprises an metal material having a honeycomb structure.
 4. The energyabsorbing table of claim 2, wherein each energy absorption core has aheight in a range of 0.6 to 1.0 inches, a width in a range of 0.6 to 1.0inches, and a length in a range of 5.0 to 7.0 inches.
 5. The energyabsorbing table of claim 4, wherein each energy absorption core islocated in a receptacle with an interior having a width substantiallyequal to the width of the energy absorption core, a height substantiallyequal to the height of the energy absorption core, and a length greaterthan the length of the energy absorption core.
 6. The energy absorbingtable of claim 1, wherein the crush chamber assembly comprises a pair ofreceptacles, wherein: each receptacle has a closed end and an openedend, the pair of receptacles are arranged such that the closed end of afirst receptacle is adjacent the opened end of a second receptacle, andthe opened end of each receptacle is aligned with and is sized toreceive an end portion of a respective one of the pair of plungerassemblies.
 7. The energy absorbing table of claim 6, wherein a firstcore of the pair of energy absorption cores is located in the firstreceptacle and a second core of the pair of energy absorption cores islocated in the second receptacle.
 8. The energy absorbing table of claim1, wherein that at least one energy absorbing assembly comprises: afirst energy absorbing assembly located in a region of the sidewallsupport, and a second energy absorbing assembly located in a region ofthe support post.
 9. The energy absorbing table of claim 1, wherein thatat least one linear guide assembly comprises: a first linear guideassembly located in a region of the sidewall support, and a secondlinear guide assembly located in a region of the support post.
 10. Theenergy absorbing table of claim 1, wherein the tabletop comprises anunderneath surface and the pair of plunger assemblies are secured to theunderneath surface.
 11. The energy absorbing table of claim 1, whereinthe tabletop comprises an underneath surface and the linear guide of theat least one linear guide assembly is secured to the underneath surface.12. The energy absorbing table of claim 1, wherein the table supportassembly comprises a top surface and the crush chamber assembly issecured to the top surface.
 13. The energy absorbing table of claim 1,wherein the table support assembly comprises a top surface and the pairof mounts are secured to the top surface.
 14. A table assembly formounting to a table support assembly, the table assembly comprising: atabletop, at least one energy absorbing assembly having: a pair ofplunger assemblies secured to the tabletop; and a crush chamber assemblyconfigured to be secured to the table support assembly, and to receivean end portion of each of the pair of plunger assemblies, the crushassembly including a pair of energy absorption cores, each energyabsorption core aligned with a respective one of the end portions, andat least one linear guide assembly having: a linear guide secured to thetabletop, and a pair of mounts configured to be secured to the tablesupport assembly, wherein the pair of mounts are aligned and configuredto receive the linear guide.
 15. The table assembly of claim 14, whereinthe crush chamber assembly comprises a pair of receptacles, wherein:each receptacle has a closed end and an opened end, the pair ofreceptacles are arranged such that the closed end of a first receptacleis adjacent the opened end of a second receptacle, and the opened end ofeach receptacle is aligned with and is sized to receive an end portionof a respective one of the pair of plunger assemblies.
 16. The tableassembly of claim 15, wherein a first core of the pair of energyabsorption cores is located in the first receptacle and a second core ofthe pair of energy absorption cores is located in the second receptacle.17. The table assembly of claim 14, wherein that at least one linearguide assembly comprises: a first linear guide assembly having a firstlinear guide secured in a region of a first end of the tabletop, and asecond linear guide assembly having a second linear guide secured in aregion of a second end of the tabletop.
 18. The table assembly of claim14, wherein the tabletop comprises an underneath surface and the pair ofplunger assemblies are secured to the underneath surface.
 19. The tableassembly of claim 14, wherein the tabletop comprises an underneathsurface and the linear guide of the at least one linear guide assemblyis secured to the underneath surface.